AMReX-Astro / AMReX-Astro/Castro

nonlinear elimination for radiation diffusion solve

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radiation
Dominant language
C++
Stars
340
Forks
105
Avg merge
3d 8h
Merged PRs (30d)
8

Description

For the radiation diffusion or moment equations, after discretizing in time, one can eliminating all variables in the radiation equations except the radiation energy density. After obtaining the radiation energy density from a multigrid solve, the eliminated variables (e.g., material energy) can be recovered independently in each cell via Newton iteration. This could potentially reduce the cost of the radiation solve significantly.

See https://www.osti.gov/pages/biblio/1660523.

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Research direction

Start with the radiation diffusion or moment-equation implementation and read the cited OSTI paper to understand the proposed elimination and Newton recovery approach. Done would require a defined implementation, correctness validation, and evidence that it reduces the cost of the radiation solve.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
hpc
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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